Due to the shortcomings of the existing set-top box (STB) chip in terms of security, it is quite common for users to watch restricted programs without payment, and even users' passwords may be frequently stolen. In order to protect interests of operators, set-top box manufacturers and users, improvements to products' safety performances need to be considered from the chip design phases. Therefore, digital TV chips with advanced security features are designed.
However, there are some ways to get away or get around with the advanced security features. One is to detect the data access to DRAM over the DRAM interface, thus obtaining users' passwords and other critical security data. The other is to embed programs into the software installed by users to get directly from the DRAM and export security data (such as users' password, the plaintext copyrighted programs, etc.). Therefore, it is desirable to provide methods to handle the problems.